Study On An Industrial Computer Based Software Programmable Logic Controller

The control system based on the computer is being widely used with the rapid development of the computer science and technology in the industrial control domain. Programmable Logic Controller has been playing an important role in the manufacturing programmed control. And along with the formulation of the IEC61131-3 standard, the Soft PLC is developing more rapidly. Different from the hard PLC, the soft PLC based on the computer not only realizes kinds of characteristic such as the function, the reliability, the speed and the trouble shooting, but also provides all kinds of flexible application under the computer environment. Furthermore, Soft PLC is more competitive for its low cost, because it is greatly applied to general hardware platform which is produced in large scale. Therefore, Soft PLC has good development prospect in the industrial control domain.At present, there are some products of the Soft PLC in the overseas, and the main manufacturers include Simens in Germany, ABB in the US and so on, so the competition is very intense in the Soft PLC market overseas. The development of the Soft PLC in the home is also at beginning, and there are a few products in the related market. But the development of the Soft PLC market domestically has great potential, and the Soft PLC has board prospects for development which develops under the general computer platform.Soft PLC has the high request about the function, the capability, the usability and the reliability. And Soft PLC is made up of the Editor, the Compiler and the input and output. The framework used the MVC model can resolve the question of the hierarchization of the Soft PLC, and enables the software to have a better extendibility. The express of the Ladder Diagram which uses the model based on the Binary diagram can complete the operation about insert, delete and amend of the editor of Soft PLC, and also provide handy algorithms. The test result indicated that the Soft PLC used real-time Linux which uses the industry computer and the switch quantity input-output card as the hardware platform can adapt to the actual industrial control circumstance, and satisfies the real application the demand.